Telemarketers, spammers, and scammers often contact individuals by telephone, which may lead to the annoyance of such individuals. The national “Do Not Call” registry is a mechanism by which individuals can opt out of unsolicited telephone calls. However, unscrupulous telemarketers, spammers, and scammers may ignore the Do Not Call registry, and may call individuals anyway. Another available option includes manually blocking phone numbers of unwanted callers on a number by number basis. This option can be tedious, and would not prevent unwanted calls from numbers which have not been identified and blocked beforehand.